The present invention relates to a microphone set, and more particularly to a small microphone set used in a small electronic instrument such as a portable telephone.
FIG. 5 is a sectional view showing a conventional one-piece microphone assembly, and FIG. 6 is an exploded perspective view of the microphone assembly.
The one-piece microphone assembly comprises a condenser microphone 1, a connector 2 secured to the underside of the microphone 1, and a gasket 4 made of elastomer such as silicon rubber and urethane rubber. Each of the connector 2 and the gasket 4 has a dish-like shape, so that the microphone is enclosed by these members. The condenser microphone 1 comprises a substrate, a back plate having a back electrode and a frame having a diaphragm electrode S. These members are mounted in a case 6.
The connector 2 is made of resin and has a terminal 3 embedded therein so as to be connected to a terminal of an electronic instrument such as a portable telephone when assembled. The gasket 4 is provided for acoustically shielding around the diaphragm electrode 5, and has a sound collection hole 4a, 
FIG. 7 is a sectional view showing another one-piece microphone assembly similar to the above described microphone assembly.
The microphone assembly comprises the microphone 1, a connector 7, and a cylindrical gasket 8. The microphone 1 is also enclosed by the connector 7 and the gasket S.
In the conventional microphone assemblies, the gasket, microphone and connector are manufactured at different manufacturers, respectively. These parts are assembled by a final assembling factory. Consequently, there are troubles about storage management of parts and the number of assembling steps.
FIG. 9 shows a microphone assembly which resolves the above described troubles.
Referring to FIG. 8, the condenser microphone assembly 10 comprises a microphone 11, a connector 12 secured to the underside of the microphone 11 and a gasket 14 secured to the upper surface of the microphone 11. As shown in FIGS. 9a to 9c, each of these members has a square in plan view. Therefore, the microphone assembly has a cubic shape or square pillar shape.
Referring to FIG. 10, the microphone 11 comprises a substrate 15 having printed circuits, a field-effect transistor (FET) 16 securely mounted on the substrate 15, having terminal electrodes on the underside thereof, a back plate 17 having a recess is for the FET 16 and vents 20 and secured to the substrate 15, a stationary back electrode 21 securely mounted on the surface of the back plate 17, a diaphragm electrode 23 as a movable electrode secured to a spacer 24 mounted on the back plate 17, and a frame 22 mounted on the diaphragm electrode 23. The spacer 24 has an opening 25. The substrate 15, back plate 17, and frame 22 are made of ceramic. The stationary back electrode 21 and the diaphragm electrode 23 form a condenser.
The connector 12 is made of anisotropic conductive elastomer and includes a plurality of gold wires or metal powders therein for electrically connecting the terminal electrodes of the substrate 15 of the microphone 11 and terminals of an electronic instrument in which the microphone assembly is to be mounted. On the underside of the connector 12, there is provided a plurality of projections 12a which are formed so as to increase local contact pressure against the terminals of the instrument and to ensure the connection there-between.
Although the microphone assembly 10 has various advantages, the microphone assembly has a cubic shape or a square pillar shape, since the assembly is manufactured by cutting the assembly aggregation. There is a case that the microphone assembly having a cubic shape can not be mounted in an electronic instrument because the space for holding the assembly has a cylindrical shape.